1. Field of the Invention
The invention relates in general to hydraulic elevator systems, and more specifically to holeless, or semi-holeless hydraulic elevator systems.
2. Description of the Prior Art
In a hydraulic elevator system, the allowable length of the plunger nearly doubles with the use of a plunger-follower guide. Thus, a much smaller jack may be used, as calculated according to the ANSI-ASME A17.1-1981 safety code for elevators and escalators. The use of a smaller jack is especially desirable in the hydraulic elevator system disclosed in U.S. Pat. No. 4,361,209, which is assigned to the same assignee as the present application. The hydraulic elevator system disclosed in that patent utilizes a tunnel member which is part of the car frame, and which extends vertically upward through the elevator car to eliminate the need for, or to minimize the depth of, a hole for the hydraulic jack. Reducing the size of the hydraulic jack in this application reduces the cross-sectional area of the tunnel, which in turn reduces the horizontal dimension of the swing return which faces the front of the elevator car. Reducing this dimension reduces the size of the hatch, for a given useful floor space in the elevator car.
The hereinbefore-mentioned U.S. Pat. discloses the use of a stabilizer assembly within the tunnel, which is always fixed to a selected portion of the hydraulic jack, i.e., to the section of the hydraulic jack which is immediately below the uppermost plunger section. The stabilizer assembly includes four rollers which are biased against the four inner corners of a square-configured tunnel. This was an improvement over prior art stabilizing means which utilizes complicated support arms, clamps, and the like, which must be synchronized with car movement.
While the stabilizer-roller assembly of U.S. Pat. No. 4,361,209 functions well, its use is effectively limited to telescopic jacks. On a single stage jack the bottom of the tunnel would not be able to move higher than the cylinder head, as the stabilizer assembly is fixed to the cylinder head. Thus, it would be desirable to provide new and improved stabilizer means for a single-stage jack/tunnel structure which provides the requisite plunger support, without the limitation of maintaining the cylinder head within the tunnel.
In my co-pending application Ser. No. 663,527, filed Oct. 22, 1984, entitled "Hydraulic Elevator System", a stabilizer member in the tunnel is releasably latched to the cylinder head of a single stage hydraulic jack, while the cylinder head is within the tunnel. As the tunnel leaves the cylinder head during the ascension of the elevator car, the stabilizer member is automatically released from the cylinder head. The stabilizer member, which requires no moving parts, then moves the plunger and tunnel, providing a lateral support point for the plunger, at the most advantageous position. The stabilizer member increases its support as the elevator car continues to rise, with this additional support point functioning without any relative motion between the stabilizer member, plunger or tunnel. The support provided by the stabilizer member extends from the plunger, through the stabilizer member to the tunnel, which in turn is part of the car frame or sling. The frame is firmly supported against lateral movement by the guide rollers which rotate against guide rails fixed in the hatch of the associated building.